Regarding the privacy, telegram is privacy oriented as long as they principles do not change, i will consider it cautiously pro privacy.
no it isn't
telegram servers know your phone number, and who you're talking to, even if the chat is encrypted. and considering most people just download the Google version, who knows what's really going on in that app
speaking about telegram and privacy:
https://www.zdnet.com/article/hong-kong-protesters-warn-of-telegram-feature-that-can-disclose-their-identities/tl:dr police adds their numbers in groups and requests the list of all the phone numbers in this group
and imagine that - the most privacy oriented messenger out there sends them
think twice before trusting mass media and articles about the most secure , privacy oriented etc.